Rotary scratcher



Nov. 19, 1963 J. E. HALL, SR

ROTARY SCRATCHER Filed Jan. 50, 1962 INVENTOR. Jease f/mer fla/g 5/:

United States Patent 3,111,170 ROTARY SCRATCHER Jesse Elmer Hall, Sn, Weatherford, Tex., assignor to Trojan, Inc., Panama, Panama, a Panamanian corporation Filed Jan. 30, 1962, Ser. No. 169,909 2 Claims. (61. 166-173) This invention is directed to wellbore scratchers employed in cementing oil wells and refers more particularly to a rotary type scratcher operative to scratch the wellbore wall upon rotation of the pipe or casing in the well, as contrasted with vertical reciprocation of the pipe or casing in the 'wellbore.

This invention is an improvement over the construction shown in Patent 2,421,434, cementing Wells, inventor Reistle et al., issued June 3, 1947.

In cementing casing in wellbores, it is conventional to employ scratching devices to clean the rnud or clay sheath from the wellbore wall which has been deposited thereon during the circulation of the drilling fluid. The mud layer on the wellbore wall impedes the formation of a proper cement bond at the said wall.

A number of scratching devices have previously been provided to clean the mud sheath from the wellbore wall upon vertical reciprocation of the pipe in the wellbore or rotation of the pipe within the wellbore or both. In the case of the so-called rotary scratchers, which achieve a more effective action upon rotation of the pipe in the wellbore, a number of serious problems have been found to exist in the art. For example, simple effective means for easily mounting the elongate vertical housings of such scratchers on the pipe have not been available. Secondly, excessive space is taken up on the wellbore annulus by the conventional rotary scratchers. Further, convenient cheap securing means for the abrading elements in the scratcher body have not been provided in such art devices. The housings of known rotary scratchers present excessive space and opportunity for channelling of wellbore fluids under the body or housing of the scratcher. Additionally, such devices usually provide an elongate, multiple perforated, channel passage which tends to fill with mud or well fluids which operates to foul and defeat the desired cement bond. The scratching or abrading units of such devices are not isolated from one another or the general wellbore annulus environment whereby there is excessive opportunity to inhibit and damage the operation thereof in the conventional wellbore processes.

Therefore, an object of the invention is to provide a rotary type scratcher with simple band-type mounting means wherein the scratcher body is part of the bands, the bands may be applied in any desired number, and wherein the entire scratcher assembly is quite simple and easy to manufacture, including the mounting means.

Another object of the invention is to provide a rotary type scratcher having a scratcher element housing body which closely conforms in the edges and a plurality of transverse central portions thereof to the pipe itself, whereby the presence of an elongate channel passage therein which readily fills with mud and fouls the cement job is completely avoided.

Another object of the invention is to provide a rotary scratcher having a scratcher element housing body so structured as to prevent channelling thereunder, and also make it difiicult to prize the body away from the pipe mounting same.

Another object of the invention is to provide a rotary type scratcher having limited housing recesses provided therein for the scratcher elements and recesses not connected in any way with one another.

Yet another object of the invention is to provide a rotary type scratcher having individual recesses thereon housing individual scratcher element assemblies, the recesses also providing unique, cheap and simple yet effective means for mounting the said scratcher element assemblies therein.

Other and further objects of the invention will appear in the course of the following description thereof.

In the drawings, which form a part of the instant specification and are to be read in conjunction therewith, an embodiment of the invention is shown and, in the various views, like numerals are employed to indicate like parts.

FIG. 1 is a front view of the subject rotary scratcher assembly on a wellbore pipe or casing, a portion of one of the scratcher element housing recesses cut away to better illustrate the construction thereof.

FIG. 2 is a side view of a casing or pipe mounting the construction of FIG. 1, taken from the left in FIG. 1 and along the line 22 of FIG. 1 in the direction of the airows.

FIG. 3 is a section through the casing above the top of the scratcher of FIG. 1 showing a top view of the rotary scratcher assembly.

Referring to the figures, at 19 is seen a pipe or casing adapted to be inserted in a wellbore. Mounted on the casing 10 is an elongate plate generally designated 11 having upper and lower edges 12 and 13 and elongate vertically oriented side edges 14 and 15. As best may be seen in FIG. 3, plate 11 is formed or configured in transverse cross section so as to lie in continuous contact with the outside surface of pipe 19 except where otherwise specifically configured. -Plate 11 is adapted to be fixed in vertical orientation on the pipe 1% with the long axis of the plate parallel to the elongate axis of the pipe.

'Formed into the plate 11 are a plurality of recess housings 16-20, inclusive, which extend outwardly from the convex side of the plate 11. The housings 1641), inclusive, are vertically arranged on the plate 11 and preferably symmetrically positioned inward from the vertical side edges 14 and 15 thereof. The housings are vertically spaced from one another by a plurality of transverse strips 21-24, inclusive, which are plate 11 portions which do not depart from the normal configuration thereof, whereby to lie against the outer surface of the pipe 10 and isolate the recess housings 16-20, inclusive, from one another. Additionally, the upper and lower extremities of the plate at 25 and 26 are like configured to make the upper and lower housings 16 and 2t) self-contained, as Well. Each of the said recess housings 162 inclusive, is so outwardly formed as to provide a substantially flat outer face which is up Wardly raised from the plate 11, each said face having preferably at least two perforations lea-20a, inclusive, and 1615-2011, inclusive, vertically spaced from one another.

On the upper surface of the plate 11 on each side of the housings 16, 13 and 2% are fixed hinge members 27a and 12, 28a and b and 29a and b, by welding or other conventional means of attachment. Three flexible metallie straps 30, 31 and 32 having each at the ends thereof hinge engagements 3% and 11, etc., are engaged with the strap members 27a and 12, etc. by suitable angled wedge pins 33 whereby to adjustably tighten and fix the plate 11 onto the pipe 10. Pins 33 are separate angled pins used in pairs to tighten the straps or strut members 27a and 12, etc.

Scratcher means are provided for each recess housing 16-20, inclusive, of particular structure as follows: A single elongate steel wire, in each case, is configured to provide (1) upper elongate tines 34-38, inclusive, (2)

first coil assemblies 39-43, inclusive, fixed to the inward end thereof, (3) second lower, lesser length tines 44-48, inclusive, (4) second inward coil assemblies 49-53, inclusive, fixed to the inward end thereof and (5) bridging wires 54 58, inclusive, which connect the two coils as best seen in the center cut away housing of FIG. 1 and in the lower cut away housing of FIG. 2. Sets of pairs of lances 59-62, inclusive (not seen in the center housing of FIG. 1) are formed from each housing outer face whereby to engage the bridging wires 54-58, inclusive,

in each housing. The detailed construction of the coil assemblies 39, etc. and 49, etc. comprises a pair of 360 small coils of lesser outer diameter than the inner diameter of the perforations in the housings whereby to be received thereinconnected to the inward end of the tines, with a less than 360 larger coil of greater inner diameter than the inner diameter of the perforations connected at one end in each case to bridging wires and the other end to the small coils as bestseen in the upper portion of the cut away housing of FIG. '1.

In oper'ation,-the plate 11 is laid on the pipe; each strap is individually engaged with the hinges opposite the housings, the wedging members are tapped in to tightly fix the plateon the pipe and then the pipe may be moved into the hole. In vertical movement of the pipe in the wellbore, either motion toward the area to be Worked or vertical reciprocation thereof, or in rotation of the pipe,

'each'housing operates as a separate entity without oppor- 4 reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. A scratching device for use on well pipe comprising an elongate, substantially rectangular plate configured in transverse cross section to fit along said pipe axially thereof with its greatest length vertical, said plate having a convex outer side and a concave inner side, the latter adapted to lie against the casing, a plurality of separate, individual housing wells outwardly formed in said plate from the convex side thereof, said wells substantially vertically aligned on said plate,'each said well spaced in from the longitudinal edges of the plate and separated from one another by a portion of said plate recessed with respect to said well, each said well having at least one perforation in the outer portion thereof, scratching means mounted in each said well and having a portion thereof extending through said perforation able to contact the Wellbore wall and means for mounting said plate on said pipe.

2. A device as in claim 1 wherein the mounting means are connected to the plate outside the said housing wells thereon.

References Cited in the file of this patent UNITED STATES PATENTS 2,421,434 Reistle June 3, 1947 2,506,405 Wright May 2, 1950 2,735,494 Wright Feb. 21, 1956 2,808,112 'Hall 'Oct. 1, 1957 2,881,839 Wright et al. 1. Apr. 14, 1959 2,927,645 Boer et a1 Mar. 8, 1960 2,945,540 Alexander July 19, 1960 

1. A SCRATCHING DEVICE FOR USE ON WELL PIPE COMPRISING AN ELONGATE, SUBSTANTIALLY RECTANGULAR PLATE CONFIGURED IN TRANSVERSE CROSS SECTION TO FIT ALONG SAID PIPE AXIALLY THEREOF WITH ITS GREATEST LENGTH VERTICAL, SAID PLATE HAVING A CONVEX OUTER SIDE AND A CONCAVE INNER SIDE, THE LATTER ADAPTED TO LIE AGAINST THE CASING, A PLURALITY OF SEPARATE, INDIVIDUAL HOUSING WELLS OUTWARDLY FORMED IN SAID PLATE FROM THE CONVEX SIDE THEREOF, SAID WELLS SUBSTANTIALLY VERTICALLY ALIGNED ON SAID PLATE, EACH SAID WELL SPACED IN FROM THE LONGITUDINAL EDGES OF THE PLATE AND SEPARATED FROM ONE ANOTHER BY A PORTION OF SAID PLATE RECESSED WITH RESPECT TO SAID WELL, EACH SAID WELL HAVING AT LEAST ONE PERFORATION IN THE OUTER PORTION THEREOF, SCRATCHING MEANS MOUNTED IN EACH SAID WELL AND HAVING A PORTION THEREOF EXTENDING THROUGH SAID PERFORATION ABLE TO CONTACT THE WELLBORE WALL AND MEANS FOR MOUNTING SAID PLATE ON SAID PIPE. 